Sausage casings are made from pig intestines and the filling is ground pig muscle and fat. Most of us don’t really think about the different animal parts hidden in things like sausages, burgers and nuggets. Might feel a bit weird when we realise we’re eating animals with the same body parts as us?

We’re the only animal that’s never weaned and continues to drink milk as an adult – and the only one that drinks the milk of another species. If that’s not weird enough, we deny calves the milk that nature intended for them, removing them from their mothers within hours of birth so that the cow’s milk can be bottled and sold to us.

Selective breeding of chickens by the farming industry has produced breeds of birds that grow much bigger and much faster than they naturally would.

This results in enormous suffering for billions of chickens every year. Many are unable to stand after just a couple of weeks of life and they often struggle to breath as their lungs are compressed under the weight of their gigantic bodies.

They are crated for slaughter at only 5-6 weeks old – still just chicks with blue eyes and soft chirps.

Every year, the world loses around 5 million hectares of forest, and 95% of this occurs in the tropics.

The expansion of animal farming is responsible for around 41% of tropical deforestation.

That’s 2.1 million hectares every year – about half the size of the Netherlands. This equates to over 16.4 million trees lost each day because of animal agriculture.  

Chickens are killed at just 6 weeks old and pigs at 6 months – a fraction of their potential lifespan. Weird, or just sad?

Selective breeding of chickens by the farming industry has produced breeds of birds that grow much bigger and much faster than they naturally would – reaching slaughter weight at only 5-6 weeks old – still just chicks with blue eyes and soft chirps.

It’s a similar story for pigs, though slightly less extreme. They’re removed from their mothers at only 4-6 weeks old – much earlier than is natural – and fattened for six months in crowded indoor pens before slaughter.

According to researchers from Oxford University, meat, farmed fish, eggs and dairy use around 83% of the world’s farmland, and contribute 56–58% of food’s different emissions, despite providing only 37% of our protein and 18% of our calories.

They calculated that the impacts of the lowest-impact animal products exceed average impacts of substitute vegetable proteins across greenhouse gas emissions (GHG), eutrophication and acidification of waterways, and land use.

They concluded that moving from current animal-based diets to a diet that excludes animal products has transformative potential, reducing food’s land use by 3.1 billion ha (a 76% reduction); food’s GHG emissions by 6.6 billion metric tonnes of CO2eq (a 49% reduction); acidification by 50% and eutrophication by 49%.

In addition to the reduction in food’s annual GHG emissions, the land no longer required for food production could remove around 8.1 billion metric tonnes of CO2 from the atmosphere each year over 100 years as natural vegetation reestablishes, and soil carbon re-accumulates.  

Antibiotic resistance is a major threat to human health and identified by the World Health Organization as one of the most important health challenges in the 21st century.

The overuse of antibiotics in animal farming is a contributor to the increase in antibiotic resistance.

Antibiotics are routinely used in intensive farming systems to prevent and treat infections and can also be used in animal feed to increase growth. Studies have estimated that 73% of all antibiotics sold globally are used in animals raised for food.  

Decades of research on pigs has found that pigs are highly intelligent beings. In clinical trials, they have been shown to have abstract thoughts, use tools, recognise their own names, dream and follow commands.

Other tests have revealed that pigs can play video games and even differentiate between drawings they made over other pigs’ artwork!  

Research shows that pigs are at least as intelligent as dogs, and in many cases even outperform dogs on tests of cognition, memory and other measures of intelligence. For example, not only can pigs be taught how to fetch like dogs, but they can also differentiate between objects (for example a ball vs. a frisbee).  

Sadly, most are hidden inside factory farms. Every day more than 202 million chickens are killed for meat. That’s 140,000 chickens every minute!

Most chickens are killed at around 6 weeks old, meaning at any given moment there are about 27.8 billion chickens alive, but only about 8 billion humans. Yet we see lots of humans every time we leave our house but rarely see chickens. Why? 

The sad answer is that most chickens killed for meat spend their short lives locked inside industrial sheds, along with 50,000 or more other birds, on factory farms.

Their only escape is when they are crated onto a truck and driven to the slaughterhouse. Oxford University researchers estimate that between 74-90% of all chickens farmed globally are factory farmed, with US Department of Agriculture data showing that in the US this figure is 98%. 

Because of the size of typical commercial male turkeys, it’s difficult for the male to get close enough to a female without injuring her because she’s much smaller and lighter. As a result, most breeding is carried out using artificial insemination. 

Some breeds of cows farmed for beef have been bred to be more muscular to increase the amount of meat they produce. A combination of calves growing very large during pregnancy and the mothers having narrow pelvic canals can result in problems giving birth. Repeated caesareans may be needed to allow them to calve. 

Most cows farmed for dairy are artificially inseminated within three months of giving birth to ensure they produce one calf a year to keep milk production high. 

Artificial insemination is also now the predominant way of impregnating pigs on commercial farms around the world. 

While there is no regularly updated data source that tracks farming conditions and the number of animals who are factory farmed, several organisations have used published data to estimate these figures. 

Using data published by the USDA Census of Agriculture and the US Environment Protection Agency, it is estimated that 99% of farmed animals in the US were factory farmed in 2017. That was 10 billion animals. More than the global human population. 

Global figures are harder to find, but based on the best available data, it is estimated that 75% of land-based farmed animals (excluding farmed fish and other aquatic animals) are factory farmed. Most fish farmed around the world are reared in factory-type conditions, so the total for all farmed animals would be higher. 

Salmon and trout are carnivorous fish and on farms they’re fed a diet containing wild-caught fish. It takes much more than 1kg of wild fish to produce 1kg of farmed fish.

Ninety percent of these wild fish, such as anchovies, mackerel and sardines, could be eaten by people directly. This means a net loss of edible human food when these fish are fed to farmed fish.

Additionally, many of these wild fish are sourced from low-income countries, contributing to food insecurity and the industry’s carbon footprint. 

Many types of meat and dairy products are high in saturated fat which can raise the risk of high cholesterol, heart disease and type 2 diabetes.

Processed meats such as sandwich slices, bacon and sausages are often also high in salt and other additives linked to heart disease and cancer.  

Multiple epidemiological studies (studies of large groups of people) have found that those following a plant-based diet rich in vegetables, fruits, whole grains, legumes and nuts had a significantly lower risk of developing heart disease than those following non-plant-based diets.

Further studies have found that greater consumption of nutritious plant-based foods was linked to a lower risk of breast cancer, aggressive forms of prostate cancer and digestive system cancers including pancreatic, colon and rectal cancers.

Similarly, several studies have shown that people following this type of healthy plant-based diet had a reduced risk of developing type 2 diabetes (34% lower risk in one major study) than those following unhealthy non-plant-based diets.